Pressure fluid motor



Aug. 30, 1932. M. c. HUFFMAN 1,874,190

PRESSURE FLUID MOTOR Filed July 5, 1929 Patented Aug. 30, 1932 om-ran. as mus Eminent e u .manvm :omnmozu, AssmNon :ro smrvnir mummy comrm,.n .conrom'rxon or ,mssncnusm'rs ERESSIIRE FLUID JIIIOTOR limitation-alga zrul 's, 1929; Seir1a1-1 V,o.376,088'.

This invention relates=to pressure l'fluid motors and more particularly to pressure fiu'id motors" of the 'impact type especially adapted to use in zrook drills OIiSll'IlllfiI types of impact tools. v p

An'object 'ofthis invention is to provide an improved pressure fiui'd m'otor. Another object is to provide an improved :pressure fluid motor ihavingiimproved fluid controlling and ilistribu'tion means. A further object is to provide an improved pressure fluid motor having an improvedautomatic distributing valve for controlling the motor flui'd supply and "exhaust 4 and "having improved -actuating means whereby the valve-is shifted "inone position by fluctuating pressures within the 'motor cylinder l and in an "opposite position by compressionbuilt up in themotor cylinder by the motor piston. Another object 'is to provide animp'roved controlling 'valve and "fluid distribution: means =or a pressure fluid 'motor -of the impact type. *These .and other objects of this invention will, however, :here- 'inafter more iully appearin the course of the following description and as more-particularl y pointed out {in the appended claims.

In the accompanying drawing there is shown ior purposes of illustration oneembodiment which the invention may assume in practice. a p V ln this drawing, v

Fig. 1 is a somewhat diagrammatic view "illustrating illustrative embodiment of the improved pressure fluid motor. I

Fig; 2 is a wiew similartoFig; 1, showing the parts in a different position.

In this illustrative embodiment -of'the invention thereisshown a pressure fluid motor of the impact type, suchas is commonly used in'rock'drills or similar types of impact-tools, comprising amotor cylinder 1 having a bore 2 in which a hammer piston 3 is *reci'p'rocably mounted. As isusua'l in motors o'f the type disclosed, the hammer' piston 3 is provided with a forward extension 4 of a reduced diameter fittinga bore 5 in the front head of the motor and'this extension is herein in the form of a strikingjbar which is adapted to deliver repeated blowsfon the-shank of a usual drillsteelor similar tool.

.Now referring:moreparticularly fto' the'imp'roved fluid controlling and distribution me'ans,-*it will benoted that formed in alatera l projection 'or boss 6, herein preferably ffo'rmed' integral :withithe motor cylinder, is. a

walve chamber having alined differential bores 7 and 8inw'hich an automaticffluid distribution valve 9 is reciprocably mounted. 'Th is 'valve is herein of the two-spool differential type having spools10 and 1 1 of the same diameter fitting the bore 8 andconnected by an intermediatereducedportion "12, As illustratedytherearward end ofthe valve is provided with an enlarged radial flange 13 of a diameterfitting'thebore 7 Formed centrally withinithe valve 9 throughout a substantial portion o'f itslengthgis-a bore 14c1osedatits forward end by'a' transverse wall I5 forming the forward end surface of-the valve. Fitting this 'bore 14 is acy'lindricalproj'ection 16,

"herein formed integral with a 'valve plug 1-7 suitably fixed-within a' bor e 18 between the rear motor 'head and the motor cylinder and having a cylindrical portion "19 fitting the "bore'7, as'clearly shown in the drawing. "This member has formed therein a chamber 20 vented through lateral slots 23 formed in-the end ofthevalve buffer anda passage 24 to the iatmosphere. 1A passage 25, extending through theprojec tion 16, connects the bore 14 within the valve with the vented chamber 20 within the valve bufifer. Theforward end ofthe :progedtion l6 limits "movement of the "valve int c rearward direction, while'forward movement of the valve is limited by a projection126 against which the end M1115 of the valve is'adapted to abut. In order to reduce the weight of the valve to a minimum the gorward end surface is grooved 'annularly at2..'-'

' In this instancethe motive fluid-supplypassage 28 extends longitudinally along one side of the valve and communicates with the bore 7 -7 adjacent the forward endthereof by a lateral port 29 communicating with an-enlarged annular groove 30. A'passage 31 connects-the rear end of thefbore 7 with the rear endof the cylinder bore 2, while a similar passage 32 communicates with the front end of the cylinder bore through a port 33 and connects the bore 8 at --tive fluid flows the port 29, through the groove 30 at the-front end offthe bore 7 past the rear'surface of the valve through the bore 7 and through through the portion on pressure -cylinder thereby causing the piston to .be driven for- 29 and, annular groove '30 the front end of the cylinder with an enlarged annular groove 34 formed at the rear end of the bore 8. An exhaust passage 35 communicates with the bore 8 between the groove 34 and the forward end of the bore 8. Communicating with the cylinder bore substantially'midway between itsends is athrowing passage 36 connecting the cylinder bore with the forward end of the valve. 'A' free exhaust passage 37, controlled by the piston 3, is provided for'relievingthe pressure at each end of the piston stroke. a

The operation of the improved pressure fluid motor is as follows, When the parts are in the position shown in 1, live me through passage 28,.through 31'to the rear'end'of the cylinder passage Simultaneously the forward end of bore 2.

the "cylinder bore is connected to exhaust through port"33,j passage 32, groove 34, valve chamber past the reduced the valve andthrough exhaust passage 35 to atmosphere. As a result, the fluid flowing to the rear end of the bore facts on the rear piston area,

wardly to effect its working stroke. As the piston 3 moves forwardly, the passage 36 is uncovered by the rear'end of the piston and 1 pressure .fluidthen flows from the rear end of the cylinder bore through this passageto the bore 8 at the forward end of the valve. As the forward area of the valve is materially larger than the rear valvejarea surrounding the projection 16, and as the forward end surface of the borel4 in the valve is vented to atmosphere, the valve is thrown rearwardly from the position shown in Fig. 1, to the position shown in Fig; 2,. The forward pressure; area on the valve is 'thenvented to atthrough annular groove 34, passage32, and port 33 to the forward end of the cylinder bore. The pressure flowing through the front end of the cylinder acts on the forward piston area, thereby 'drivingthe piston rearwardly to effect its return stroke. Continued rearward movement of the piston causes the fluid trapped within the rear end of the cylinder here to be highly compressed and this comr pressed-fluid passes, through passage 31*to the efficiency and at the When the valve is bore 7 at the rear end of the valve. This relatively high compression pressure acts on the rear pressure area of the valve and causes the latter to be shifted from the position shown in Fig. 2 again to the position shown in Fig.1, thepressure at the forward end of the valvebeing relieved at that time as mentioned above. When the piston nears the end of its rearward stroke the free exhaust passage is uncovered, thereby opening the front end of the cylinder bore to exhaust. When the valve is again in the position shown in Fig. 1, live fluid is admitted to the rear end of the cylinder bore while the forward end of the cylinder bore is exhausted to atmosphere and the sequence of events described above 18 repeated, thereby causing the hammer piston to be rapidly reciprocated within the cylinder as long as pressure fluid is supplied to passage 28 As a result of this invention it will be noted that an improved pressure fluid motor is provided having an automatic fluid distribution of an extremely improved and simplified fluid distribution simple design and means,,resulting in a motor having increased same time materially reducing the cost of construction. It Wlll further be noted that an improved pressure fluid motor is provided having an improved automatic fluid distributing valve which is thrown intoone position by fluctuating pressures within one end of the cylinder and into its other position by compression built up in the motor cylinder by the motor piston. These and other advantages of this invention will, however, be clearly apparent to those skilled in this art.

WVhile there is in this application specifically described one embodiment which the invention may assume in practice, it will be understoodthat this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims. v V

What I claim as new and desire to secure by Letters Patent is:

1. A pressure fluid motor comprising a cylinder, a piston .reciprocable in said cylinder, and fluid distribution means for effecting reciprocation of said piston including means forming a valve chamber having differential bores a supply passage communicating with the larger of said bores, a passage leading fromthe larger bore to the rear end of said cylinder, a passage leading from the smaller of said bores to the front end of said cylinder, an exhaust passage connecting the smaller bore to atmosphere, a differential spool, valve reciprocably mounted in said chamber for alternately connecting said second and third mentioned passages with said supply passage and for intermittently consai end of thecylinder-ibysixid piston, said rear pressure area :being of less extent than said madman necting said third mentioned massage (with said ierthaust passage, aneans for zsubjecting the forward, pressureiareaaone said salve-intermittently to the pressure-in saidrcylinden-and means :for intermittently subjecting the op-v posedrear pressure:areaionsaidvalveto'compression built up in-the rear end of'the cy'linder by said piston, said valve chamber forming means and said valve ihaving portions cooperatingsto make the saidopposedaearpressure areaonthe "valve ofless area than the forward pressure sareaton said Waive.

:2. A pressure 'fluld motor comprising at A cylinder, a :piston :IZQClPIIOGZlblG :in .said (cylinder, :and fiuid distribution means for effecting reciprocation of said piston including larger bore to the rear endiott said-cylinden'a passage leading trom' the smaller of said bores to the afront end of said cylinder, an exhaust passage connectingithe smaller here to atmosphere, a differential spools :fitting the smaller ":bore, :one of the valve having spools of :said valve having an enlarged 'fianged portion fittingthe largerlbore, means for subjecting athe forward epressure area :on

said valve intermittentlylto the pressure in said cylinder, and :means for intermittently ecting the opposed rear pressure 1 area on 'valve to compression built up inthe rear subg forward r pressure area.

3. A pressure fluid motor :eornprising a cylinder, a piston :reciprocable in said cylder, andfluid distribution means "for-effecting reciprocation of said piston including a valve chamber having "differential bores, a supply passagecommunicating vvith the larger off said bores, a passage leading viirom =the larger tbore "to the rear end-10f said :oyli-nder, a passage leading :from the smaller of said bores'to the :trontrendo'f saidrcylinder anexhaust passage (connecting the smaller bore to atmosphere; aidifierential valveihaving spools fitting the smaller bore, onezof the spools o it said valve having an .enlargedifianged 'POI tionfitting the "largerbore, saiduvalveihaving a forward pressure area (and a smaller wopposed rear pressure area, :means for subjecting the :forward tpressure area on :said valve intermittently to the pressure 'in :said cylinder, means for intermittently subjecting the opposed rear pressure area .on said valve to compression built up in thelrear end iofithe cylinder by said :piston, andrmeans for subjecting the forward pressure areawon said flange to the pressure in said supply passage tohold said valve in oneposition. f

4. A pressure fluid motor'comprising acylinder, :a piston reciproca-ble in said cylindeigand fluid distribution means foriefiecting reciprocation of said pistonfincludingmeafls cinder, ian zeirhaust forming awalve chamberzhaving difierential Shores, :aisupply passage communicating :Wlth :the larger of rSBldibOl'ES, a passage leading them the larger there to ?the rear end .of 1 said ioylinder, a passage lea-dingwfrom the smaller 10f said 'rbores :to the from end of saidicylin'der, .an @exhaust ipassage connecting the smaller bore to atmosphere, 1a difi'erential spool valve xreciprocably mounted in said "chamber for alternativelyconnecting said :second iand'tthird mentioned passages with saidssupply passage .and for intermittently iconnecting said :third imentioned passage withzsaidlexhaust passage, said valve having a :central bore :iextending only partially through :thesame from the rear thereof, :a :projection .011 said valve chamber forming means fitting saidfbore,

means for venting said valve borefto atmosphere, means for -subj.ecting:the tforavard :pressure area-on said intermittently to theflpressure in said rcyllinder, and :means "for intermittently subzjecting'theopposed rear-pressure areaon said 'valvetocompression built-up :in the rear end :ofathe cylinder rbyzsaid piston.

-15. VAapressure :fluid motor comprising a cyl- :inder,1a piston'reciprocable in said cylinder, andrfluiddistribution means for effecting re- :ciprocation of said piston including means storming .a valve 'chamber having difierential bores, zassupply passage communicating with the larger of said bores, a passage leading from rthe larger borefto itherearend of said acylinder a passage leading from the smaller of said Ibores :to :the iiront uendlof said vcylapassage connecting :the smaller bore to atmosphere, .a "differential valve i'havingispools fitting the smaller bore, ione ofithe spoolsofsaid'valvehaving an enlargedifianged portion fitting the "largeribore, said walve having :a central :bore extending only partially through the same from the rear thereof, arprojection on saidvalve chamz'ber forming means fittingsaidsbore, means for eventing said valve bore'zto atmosphere means 'ittor subjecting the forward pressure area on said valveintermittentlystoithepressurein saidicylinder, and meansfor inter- :mittently subjecting :the :opposed'rear 'pressure sarea -on said valve to compression built up in the rear end of the cylinder iby said piston. Y Y

. a6. .Acpressure'fluidmotor-comprising a cyl- -inder, a pistonreciprocablein said cylinder,

and fluiddistribution means :tor eflecting 'respools of said valve having an enlarged flanged portion fitting the larger bore, said valve having a central bore extending only partially through the same from the rear thereof, a projection on said valve chamber forming means fitting said bore, means for venting said valve bore to atmosphere, means for. intermittently subjecting the forward pressure area on said valve to the pressure in said cylinder, means for intermittently subjecting the opposed rear pressure area on said valve to compression built up in the rear end of the cylinder by said piston, and

'means for subjecting the forward-pressure area on said flange to the pressure in said supply passage to hold said valve in one position.

7. A pressure fluid motor comprising a cylinder, a piston reciprocable in saidcylinder, and fluid distribution means for effecting reciprocation of said piston comprising a reciprocable fluid distribution valve havinga spool arranged to control admission of fluid to both ends of the cylinder and a second spool for controlling the exhaust. from one end of the cylinder, said first mentioned spool having an enlarged flange providing a forward pressure area to hold the valve in one position, a piston controlled passage for subjecting said second spool to pressure for throwing said valve to one position, andmeans for subjecting the other spool to compression built up in the cylinder by said piston for throwing said valve to its other position, said last mentioned spool having an area subjected to compression smaller than the area on said secondspool' subjected to the pressure for throwing the valve.

8. A pressure fluid motor comprising a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for effecting reciprocation of said piston comprising a differential fluid distributing valve for controlling the fluid distribution for said cylinder, and having opposed pressure areas of a different diameters, the area of larger. diameter being of smaller extent, means for subjecting the forward pressure area of said valve to pressure within the cylinder, and

'. means for subjecting said opposed area to .1 compression built up in the rear end of said .cylinder.

9. A pressure fluid motor comprising a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for effecting reciprocation of said piston comprising a differential fluid distributing valve for controlling the fluid distribution for said cylinder and having opposed pressure areas of different diameters, the area of larger diameter being of smaller extent, means for subjecting the forward pressure area of said valve to fluctuating pressure within the cylinder, means for subjecting said opposed area to compression built up in the rear end of the cylinder, and another pressure area on said valve adapted to be subjected to intermittent pressure acting in the same direction as the cylinder pressure for holding said valve in one position.

10. A pressure fluid motor comprising a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for effecting reciprocation of said piston comprising a differential fluid distributing valve for controlling the fluid distribution for said cylinder and having opposed pressure areas of diflerent diameters, the area of larger diameter being of smaller extent, means for subjecting the forward pressure area of said valve to pressure within the cylinder including a piston-controlled throwing passage connecting the cylinder with the forward end of said valve, and means for subjecting said opposed area to compression built up in the rear end of the cylinder.

11. A pressure fluid motor comprising a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for effecting reciprocation of said piston comprising a differential fluid distributing valve for controlling the fluid distribution for said cylinder and having opposed pressure areas of different diameters, the area of larger diameter being of smaller extent, means for subjecting the forward pressure area of said valve to pressure within the cylinder including a piston-controlled throwing passage conmeeting the cylinder with the forward end of said valve, means for subjecting said opposed area to compression built up in the rear end of the cylinder, and another pressure .area on said valve adapted to be subjected to intermittent pressure acting in the same direction as the cylinder pressure acting on the forward pressure area for holding said valve in one position.

12. In a pressure fluid motor, a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for effecting reciprocation of said piston including means forming a valve chamber having small and large bores, a fluid supply passage communicating with'the forward end of said large bore, a passage connecting the rear end of the large bore with the rear end of the motor cylinder, a passage communicating with said smaller bore intermediate its ends and leading to the front end of the cylinder, an exhaust passage communicating with the small bore between said third mentioned passage and the forward end of the small bore, an automatic fluid distribution valve reciprocable in the valve chamber and having spaced spools fitting the small bore and an enlarged rear flange fitting the large bore, means for valve with the cylinder, and means for subjecting the opposed rear pressure area on said valve to compression built up in'the'rear end of the cylinder by said piston to shift said valve into its other position, said valve chamber forming means and said valve having portions cooperating to make the said opposed rear pressure area on the valve of less area than said forward pressure area on said valve.

13. In a pressure fluid motor, a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for effecting reciprocation of said piston including means forming a valve chamber having small and large bores, a fluid supply passage communicating with the forward end of said large bore, a passage connecting the rear end of the large bore with the rear end of the motor cylinder, a passage communicating with said smaller bore intermediate its ends and leading to the front end of the cylinder, an exhaust passage communicating with the small bore between said third .mentioned passage and the forward end of the small bore, an automatic fluid distribution valve reciprocable in the valve chamber and having spaced spools fitting the small bore and an enlarged rear flange fitting the large bore, means for subjecting the forward pressure area on said valve to throwing pressure to effect shifting of said valve into one position including a piston-controlled throwing passage connecting the small bore at the forward end of the valve with the cylinder, means for-subjecting the opposed rear pressure area on said valve to compression built up in the rear end of the cylinder by said piston to shift said valve into its other position, and means for subjecting the forward pressure on said flange to live pressure to hold said valve in one posltion, said valve chamber forming means and said valve having portions cooperating to make the said-opposed rear pressure area on the valve of less area than said forward pressure area on said valve.

14. In a pressure fluid motor, a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for effecting reciprocation of said piston including a valve chamber having small and large bores, a fluid supply passage communicating with the forward end of said large bore, a passage con necting the rear end of the large bore with the rear end of the motor cylinder, a passage communicating with said smaller bore intermediate its ends and leading to the front end of the cylinder, an exhaust passage communicating with the small bore between said third mentioned passage and the forward end of the small bore, an automatic fluid distribution valve reciprocable in the valve chamber and having spaced spools fitting the small bore and an enlarged rear flange fitting the large bore, means for subjecting the forward pressure area on said valve to throwing pressure to effect shifting of said valve into one position including a piston-controlled throwing passage connecting the small bore at the forward end of the valve with the cylindenmeans for subjecting the opposed rear pressure arearon' said, valve to compression built up in therear end of the cylinder by said piston to shift said valve into its other position; and means for venting a portion of the opposed rear. to atmosphere. I

y 15. In.a-pressure-fluidmotor, piston reciprocable in said cylinder, and fluid distribution means for effecting pressure area on said valve sage communicating with the forward end of said large bore, a'passa'ge connectingthe rear end of the large bore with the rear end of the motor cylinder, a passage communicat-- ing with said smaller bore intermediate its ends and'leading to thefront end of theficylinincluding a piston-controlled throwing passage connecting the small bore at the forward end of the valve with the cylinder, means for subjecting the opposed rear pressure area on said valve to compression built up in the rear end of the cylinder by said piston to shift said valve into its other position, means for subjecting the forward pressure area on said flange to live pressure to hold said valve in one position, and means for venting a portion of the opposed rear pressure area on said valve to atmosphere.

16. A pressure fluid motor including a cylinder, a piston reciprocable in the cylinder, and fluid distribution means for effecting reciprocation of said piston including means forming a valve chamber having a plurality of bores of different sizes, a valve reciprocable in said valve chamber and having portions cooperating with said different bores, means for conducting live pressure fluid to said valve chamber, means for connecting longitudinally spaced portions of said valve chamber with an end of the cylinder and an intermediate point in the latter, and a valve having a forwardly facing surface on which line pressure acts continuously, a larger opposed surface on which line pressure acts during admission of the above mentioned end of the cylinder to effect strokes of said piston in one direction, and a still larger surface facing similarly to the first mentioned surface to a cylinder,- a'

I reciprocation of said piston-including a valvechamber having smallandlarge bores, a fluid supplypaswhich pressure isadmitted when said piston reaches in said strokes said intermediate point in the cylinder. v

17. A pressure fluid motor including a cylinder, a piston reciprocable in the cylinder,

and fluid distribution means for efi'ecting reciprocation of said piston including means forming a valve chamber having a plurality of bores of different sizes, a valve reciprocable in said valve chamber and'having portions cooperating with said'difi'erent bores,lmeans for conducting live pressure fluid to said valve I chamber, means for connecting the valve. chamber to opposite ends of the cylinder and to a point intermediate the ends of the cylinder, and means for connecting the valve chamber to atmosphere, said valve having a forwardly facing surface on which live pressure acts continuously, a larger opposed surface on which live pressure acts at the beginning and during a portion of each stroke of the iston in one direction, and a still larger sur acefacing similarly to the first surface to which pressure is admitted adjacent the end of such strokes.

In testimony whereof I aifix my signature.

MERVIN C. HUFFMAN.

CERTIFICATE OF CORRECTION.

Patent No. 1,874,190. August 30, 1932.

MERVIN G. HUFFMAN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, line 110, claim 5, after "atmosphere" insert a comma; page 4, line 62, claim 9, for "pressure" read pressures; and page 5, line 127, claim 16, for "of" first occurrence read to; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 30th day of October, A. D. 1934.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

